Of the $189 million spent so far by Super PACs, non-profits and labor unions to influence the 2010 mid-term elections, $97.5 million has come from groups that do not disclose any donors, an analysis of Federal Election Commission contribution records shows. That is, about 52 percent of the money spent so far on everything from political ads to phone banks to fliers promoting or opposing federal candidates has come from groups that don't disclose the sources of their funds.*

Of the 218 non-party committees that have spent money on independent expenditures or electioneering communications, only 100 have disclosed their donors to the FEC via monthly filings and quarterly reports or the 24- and 48-hour reports required for electioneering communications.

Some of those organizations might still disclose their donors to the FEC; others, such as the U.S. Chamber of Commerce, a non-profit, 501(c)6 organization and Crossroads GPS, a non-profit 501(c) 4, are not required to disclose their donors. Other organizations that are required to disclose donors, known as 527s after the section of the tax code they're organized under, might not have to file their quarterly disclosure reports until after the Nov. 2 election.

The Sunlight Foundation Reporting Group is adding all available contribution data filed in quarterly reports and monthly statements with the FEC to our Follow the Unlimited Money tool.

The 100 groups that have disclosed donors through today's date show that in many cases special interests are driving the funding. For example, the First Amendment Alliance has received a great deal of its money—used to oppose Democrats including Sen. Michael Bennet of Colorado, Sen. Harry Reid of Nevada and Gov. Joe Manchin, the West Virginia Senate candidate—from corporations and individuals with direct ties to the oil industry. First Amendment Alliance organized in early September as a "Super PAC" or independent expenditure-only commitee and stated its intention to receive unlimited contributions by submitting a letter required by the FEC. The group revealed the sources of its $1.4 million in contributions in their October Quarterly report.

The donation data also shows that Bob Perry—the single largest donor to Swift Boat Veterans for Truth at $4.45 million—has given $100,000 to the Super PAC. He's tied with two other donors for the for the second biggest contribution, Earl Rodman, Jr. of Rodman Petroleum and Clayton Williams, Jr. of Clayton Williams Energy Inc. The largest contributor is listed as Gordy Russell whose occupation is recorded as self-employed.

Of the group's 77 contributors, 36 are corporations.

The most recent quarterly reports dislose all contributions and expenditures from July 1st, 2010 through September 30, 2010. Monthly reports are due today, Oct. 20. Some of those reports have come in already and contain contributor and expenditure information.

*–Note: An earlier version of this post noted that groups that disclose their donors have raised $98.6 million. Some of these groups have not spent all of their funds yet. Some readers were confused that the $98.6 million raised by groups that disclose their donors plus the $97.5 million spent by groups that do not disclose their donors did not total to $189 million. The latter figure includes all money spent by non-party committees; groups that don't disclose their donors have spent $97.5 million of that total, or 52 percent. The other 48 percent of the total — roughly $90 million or so — has been spent by groups that do disclose their donors. We regret the confusion created.